Title: Laminated identification document with protection against falsi¬ fication by delamination
The present invention relates to an identification document compri¬ sing a base card with one or more specific marks, a photographic layer with a photographic reproduction, comprising an image section containing the image of the person concerned, and a text section, in which the particulars or data with respect to the same person are mentioned, and a transparent coating, which by lamination is fixed inseparably to at least the photographic layer, the marks extending both over the image section and the text section.
An identification document of this kind is known from US patent specification 3 152 901, wherein the transparent coating is fixed to the photographic reproduction by means of a non-curing adhesive, with the disadvantage that by softening of the adhesive, such as e.g. by increas¬ ing the temperature, the document can be opened, so that it can be faked, and then closed again without the possibility to detect the falsification visually within a short time.
The object of the present invention is to eliminate this disadvan¬ tage and to provide an identification document with which any attempt of falsification can be visually detected clearly and within a short time.
According to the invention this object is achieved by the following features: a) the adhesive consists of an irreversibly curing glue; b) the photographic layer comprises at least three different colour layers; and c) at least one transparent coating carries at the inside a number of differently coded marks.
By using the present invention any attempt to falsify one or more parts of the base card and the information recorded thereon is immediate¬ ly made visible when examined visually or under ultraviolet radiation, as upon delamination the cleaving of the photographic layer at two or more different colour layers and/or at the junction between the marks and the one, or more transparent outer layers make it impossible to repair the en¬ tire identification document or its base card later on.
A preferred embodiment of the invention is characterized in that the differently coded marks comprise a number of normally invisibly coded marks which fluoresce under ultraviolet radiation.
This has as a consequence that upon opening the laminate cleavage is brought about in such a way that the marks that fluoresce under ultra¬ violet radiation are detached between the transparent film and the mark, whereas at locations where no marks are- present cleavage is brought about between the photographic colour layers.
In another appropriate embodiment the invisibly coded marks that fluoresce under ultraviolet radiation are coded in at least two colours.
These marks, coded in different colours, reveal immediately and clearly any disturbance of their pattern by delamination and attempted falsification.
A practical embodiment of the invention is characterized in that the marks that fluoresce under ultraviolet radiation fluoresce partially green and partially red.
This provides an even faster detection of the disturbance of the marks pattern.
The invention will now be illustrated further with reference to the accompanying schematic cross-sectional drawing of an example. Herein the left hand part shows the undisturbed laminate of the finished identifica¬ tion document, whereas the right hand part shows the laminate of the same identification document, delaminated at the upper side and consequently damaged. The undisturbed laminate of the identification document, represented in the left hand part of the drawing, is composed by a number of super¬ posed and partially inseparably connected layers 1 to 10. The base card, comprising the image section, containing the image of the person to be identified, and the text section, containing the particulars or data with respect to the same person, is constituted by the layers 2 to 9*. Bottom- layer 1 consists of a transparent polyester bottom film, on top of which the bottom side of the polyester image carrying layer 3 is fixed insepa¬ rably by means of an irreversibly curing glue layer 7A. Preferably the bottom film 1 carries at the inside a print 2 in the form of text and/or one or more pictures and also marks in the form of a pattern of parallel thin lines (e.g. numiscan).
Image carrying layer 3 carries three different colour layers, which constitute the colour photograph. Those are, going in the upward direc-
tion, the yellow layer A, the magenta or red layer 5 and the cyan or blue layer 6.
On top of this again an irreversibly curing glue layer 7 is ap¬ plied, which constitutes the inseparable junction with a coating 8. This coating 8 consists of a transparent varnish which has a positive or nega¬ tive influence on the adhesion to other layers. This varnish is applied only to the marks 9 of ink that fluoresces under ultraviolet radiation, which marks are located at the inside of the polyester top and bottom • layers 1 and 10, but not in the intervals between the marks 9. Preferably these marks 9 are distributed in a regular way over the entire surface at both sides of the identification document.
In accordance with a preferred embodiment of the invention the in¬ visibly coded marks 9 that fluoresce under ultraviolet radiation are coded in at least two colours. In this case it is appropriate that the marks 9 when irradiated with ultraviolet radiation fluoresce partially green and partially red.
In accordance with a special embodiment each of the marks 9 that fluoresce under ultraviolet radiation changes gradually in colour from one side to the other. In a practical embodiment of the invention the top and bottom films 1 and 10 consist of polyester which is unmodified prior to the applica¬ tion of the number of marks 9 that fluoresce under ultraviolet radiation, whereas after the application of those marks 9, such as preferably by printing with ultraviolet fluorescent ink, the polyester is permanently modified, e.g. by exposition to an electrical corona discharge, optional¬ ly followed by a treatment with a primer. As a result chemically reactive groups are created at those locations where the polyester layers 1 and 10 do not carry marks 9, which chemically reactive groups later on react with the glue 7- As an additional protection against falsification the bottom film 1 carries at its inside a print 2 in the form of text and/or one or more pictures.
The right hand side of the drawing shows the consequences of de¬ lamination at the upper side of the laminate of fig. 1. Between the marks 9 of ink that fluoresces under ultraviolet radiation, which is covered with a varnish 8 that has a positive or negative influence on the ad¬ hesion to other layers, according to a random pattern, a non-limiting example of which is given in the drawing, the connection between the cyan
or blue layer 6 and/or the magenta or red layer 5 and/or the underlying yellow layer k is partially disrupted.
As a consequence upon opening of the laminate a cleavage is brought about in such a way that the marks 9 that fluoresce under ultraviolet radiation detach between the transparent film 10, 1 and the mark, whereas at locations where no mark 9 is present a different, uncontrolled cleav¬ age is brought about between the photographic colour layers 4, 5, 6.
In accordance with the process of the invention for making an iden¬ tification document the layers 3 to 6, i.e. the polyester image carrier 3, the yellow layer 4, the magenta or red layer 5 and the cyan or blue layer 6, are exposed and developed as a photograph.
In this process, when the photograph emerges from the final rinsing bath, i.e. before this photograph is dried, the still wet emulsion layer 3 to 6 can be modified by means of substances, such as e.g. a water di- lutable component containing hydroxyl groups, which later on react chemi¬ cally with the glue layers 7A and 9.
In the process of the invention for making an identification docu¬ ment as the irreversibly curing glue 7A, 7 a two-component glue is ap¬ plied by means of a printing roll, a jet technique, an intaglio technique or a screen printing technique.
In a favourable embodiment of the process for making the identifi¬ cation document after the putting together and glueing together of the entire identification document the glue layers 7A and 7 are cured through and through, optionally at an elevated temperature and/or under irradia- tion with ultraviolet, electron or gamma radiation in order to speed up the curing process. After this the identification document is ready to be issued and then to be used.
When now attempts are made to open the laminate by delamination so as to change the base card for faking purposes, in all circumstances the photographic colour layers 4 to 6 as a whole or in several combinations of colour layers will be detached from the polyester image carrier 3, as represented for example at the right hand side of the drawing and as de¬ scribed above.
Also the marks 9 may be detached wholly or partially from the bottom and/or the top film, 1 and 10 respectively. This causes total or partial destruction of the document, by which repair and/or falsification of the identification document has become impossible.